EarthWatch: Dust Cloud in Alaska

Produced by the Space Telescope Science Institute’s Office of Public Outreach in collaboration with the NASA Earth Observatory: https://earthobservatory.nasa.gov/ 

NASA Earth Observatory image by Joshua Stevens, using Landsat data from the U.S. Geological Survey Image of the Day story by Kathryn Hansen: https://earthobservatory.nasa.gov/images/147504/copper-river-valley-dust-cloud 
Adaptation to ViewSpace by Claire Blome, Margaret W. Carruthers, and Dani Player

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Text, Earth Watch, Exploring the Blue Planet by Satellite

 

An aerial view of a dust cloud in Alaska on October 22, 2020

 

Text, Dust storms are relatively common in the Sahara Desert, but they can also happen at high latitudes in places that are icy and dry.

 

This satellite image shows dust streaming over the Gulf of Alaska.

 

The dust pictured here originated upstream in the Copper River Valley, where glaciers crush rocks into a very fine silt.

 

River water then carries the silt south and deposits it in the delta and along the shore.

 

The fine silt particles are easily lofted into the air by stiff breezes.

 

Dust storms are particularly prevalent in autumn when seasonal winds pick up.

 

The arrival of cooler weather also decreases glacial melting, which causes river levels to drop, leaving more silt exposed to the wind.

 

Dust plays an important part in marine ecosystems.

 

Once the dust settles in the gulf, it provides important nutrients for phytoplankton, which form the base of the marine food chain.

 

Satellite imagery makes it possible for researchers to detect and track dust clouds almost anywhere on Earth.

 

To learn more, go to: earth observatory dot nasa dot gov